CRJ-900 flight crew reported the TRACON Controller vectored them on a conflicting course with a VFR aircraft 400 feet above them resulting in a TCAS/RA.

Narrative

We had a RA out of ZZZ on departure. We were given 4;000 ft. and right turn heading 360. We made the turn about 400-500 ft. We were told of traffic ahead and told to stay at 4;000 ft. then we were given a turn to heading 070 which put as directly in line with the GA aircraft just 400 ft. above. The controller said he would pass us. They put us on a direct course to him. We adjusted the range and within seconds; we received an RA. The First Officer was flying. He turned off autopilot and smoothly descended following procedure. I reported the altitude deviation and that we were receiving an RA. After being clear of conflict; we continued on our way to ZZZ1 without further incident. We reported the RA to ZZZ departure. Controller provided direction and altitude that put us in near proximity to GA aircraft on departure. Within 400 to 500 ft. by our observation. ATC and pilots must continue to be vigilant. It is necessary to follow controllers instructions; but those instructions should and sometimes must be questioned by pilots. Not trusting blindly that the controller is always keeping them clear and safe of traffic.